The surprisingly close defeat suffered by Jeremy Corbyn in the recent election, and his subsequent boost in the polls, has triggered a wave of doubt amongst defenders of sound public finances. Cabinet Ministers such as Boris Johnson and Michael Gove have been pushing for a relaxation of the 1% public sector pay cap, and even Chancellor Philip Hammond has acknowledged that the public are tired of austerity. The Conservatives it seems have begun to conclude that the way to fight the fire of spendthrift Corbynism is with fire of their own. But you can’t out-Corbyn Corbyn, and there won’t be any votes in offering Corbyn-lite. The Conservatives need to remember that they did actually win the General Election, and even increased their vote share over Cameron’s 2015 haul by an impressive 5 points. Indeed, at 42%, they equalled that achieved by Margaret Thatcher at the height of her popularity in her 1983 landslide. Yes, the party lost seats and, most crucially, their Parliamentary majority. But that was a consequence of the unexpected popularity of Corbyn, particularly amongst former UKIP voters, and the vagaries of the first past the post electoral system when elections are close between the top two parties. The point is not that the election was not, with hindsight, an extraordinarily poor strategic move on the part of Theresa May, and a self-inflicted disaster for the Tories (though it could have been worse). But that a 42% vote share is no reason to doubt the popularity of your policies or your overall approach to government. Getting bills through Parliament as a minority administration is another matter, however.

The Conservatives did so many things wrong in the election campaign – the absurd focus on Mrs May, the uncosted manifesto, the dementia tax – and Corbyn made so many tactically astute moves – the (ostensibly) costed manifesto, the tuition fee pledge, committing to hard Brexit even while courting Remainers – that it is difficult to pinpoint any one thing the Tories should have done differently. But one deeply important message that was almost wholly absent from the campaign was the government deficit and the national debt.

It is easy to see how this had happened. Corbyn had been so unpopular ahead of the election campaign, and his ideas on public spending so far outside of the post-1970s consensus, that the Tories had allowed themselves to become complacent when it came to their own message on the public finances. Assuming, perhaps, that they could take for granted their reputation as the party of sound finances, and that the electorate would not be taken in by Corbyn’s patently unaffordable socialism, they did not hammer home the fact that the massive debt they inherited from Labour in 2010 was still going up. They failed to mention that bringing the public finances back into shape still required more years of restrained public spending. To make matters worse, the Tories then made uncosted spending pledges of their own, leaving them without a leg to stand on when it came to criticising Labour’s spending plans.

How much of a difference for the Tories a change here would have made is hard to tell. Truth is, even through all this they did not see their standing in the polls slip very far, and their 42% vote share is still among the highest in recent times. Very little of the Corbyn surge can be attributed to prospective Tory voters switching to Labour – much of it seems to have been an unlikely mix of Remainers heeding the views of their local Remain MP over those actually printed in the manifesto, ex-Ukippers coming home to Labour enticed back by the commitment to a hard Brexit, and young people attracted by the tuition fee pledge. How many of these could have been persuaded to choose head over heart and vote Tory had the party made the deficit a central plank of their campaign? There are far too many variables in that equation to make a sensible prediction.

One thing is certain, though: the government has seen the Corbyn surge and the loss of its majority as a vote against austerity. There is much truth in that. But that doesn’t mean the right response is to give way to that demand. 40% may have voted against austerity, but 42% voted for the Tories, and they are still in power. What’s more, the Tories would not be able to deliver in practice anything like Labour are promising in opposition, and so would never succeed in wooing anti-austerity voters. Yet in the process they would destroy their own reputation for sound finances and alienate their natural constituency.

Conservatives Ministers don’t help themselves here by joining in with talk of ‘austerity’. That’s what the opponents of fiscal restraint call it, and it is a pejorative term designed to discredit it by making it sound unpleasant. It is unpleasant, but there’s nothing to be gained by drawing attention to that when you are trying to implement it. It is fiscal discipline, investing in the future, and sound management of the public finances. Call it anything else and you play straight into your opponents’ hands.

Deficit reduction isn’t merely a political imperative for the Tories, though. It is also a moral one. For debt is nothing other than spending tomorrow’s money today. On a small scale, or carefully managed, that can be very sensible and perfectly acceptable, either because all those potentially affected have accepted the associated risks and sacrifices, which are anyway manageable, or, in the case of a future generation, because even though they cannot personally assent they will benefit and so their consent can reasonably be assumed.

Nothing, however, can justify deliberately maintaining and increasing a debt on such a massive scale as the UK currently has. Whatever the needs of the present, continuously ratcheting up debt is spending money the country does not have at the expense not only of the future of the current generation but the next one too. There are always more things we want to spend money on than we have money to spend. Some of them, indeed, are matters of real and pressing need. But there is an overarching moral imperative to live within our means. Not only because of the negative economic consequences for us ourselves, though those are real: debt interest this year is estimated to be a whopping £42bn, making it the fifth largest item of government expenditure after health, welfare, pensions and education. Plus there is always the lingering threat of still being up to our eyes in debt the next time recession hits (as it always will). But also because of the negative consequences for our children and those yet unborn, and that is most definitely a moral problem.

Public spending in the pursuit of the common good and for provision for the needy can readily draw support from scripture. We are commanded to do good to all, and to love our neighbour as ourselves. But debt is another matter. Paul instructs Christians to owe no one anything, except to love one another. We are to do good to all, but out of what we have, not what we don’t have; with that which is our own, not with that which is another’s. Whatever our politics and what we think is appropriate for the state to do or not do, our bottom line must be the bottom line: we must operate within our means, not amassing debt that costs us dearly in interest and burdens our children with paying off the consequences of our own profligacy.

Christians are called to set an example of love and honourable living that wins the respect of those outside the faith and impresses them with its integrity, sincerity and faithfulness – not for our own glory, but so as to make the Gospel of our Lord attractive to those who encounter us. Whatever else we support in politics, a crucial element of this must be support for sound public finances – and with it a non-negotiable opposition to the irresponsible accumulation of debt for ourselves and our children. Gospel integrity requires nothing less.